This invention relates to a semiconductor device provided with a capacitor wherein a ferroelectric film is employed as a dielectric film, and to a method for manufacturing such a semiconductor device.
A ferroelectric RAM provided with a capacitor wherein a ferroelectric film is employed as a capacitor dielectric film has been attracting attentions as a high-speed readable and writable RAM.
In a process of forming a capacitor of a ferroelectric RAM, a step of patterning a ferroelectric film constituting a capacitor dielectric film is required. Conventionally, the patterning of a ferroelectric film of such as Pb(Zr, Ti)O3 is usually performed by means of plasma dry etching where Ar and Cl2 are employed as an etching gas.
However, when the patterning of a ferroelectric film is performed by means of the dry etching of this kind, the ferroelectric film is inevitably exposed to plasma, thereby raising various problems that the ferroelectric film may be damaged or the dielectric property of the ferroelectric film may be deteriorated, thus resulting in a decrease of the number of repetition of writing in the ferroelectric RAM.